CN103236473A

CN103236473A - Back polishing process for manufacturing back passivated solar battery

Info

Publication number: CN103236473A
Application number: CN2013101685961A
Authority: CN
Inventors: 成文; 刘文峰; 杨晓生
Original assignee: Hunan Red Sun Photoelectricity Science and Technology Co Ltd
Current assignee: Hunan Red Sun Photoelectricity Science and Technology Co Ltd
Priority date: 2013-05-09
Filing date: 2013-05-09
Publication date: 2013-08-07

Abstract

The invention discloses a back polishing process for manufacturing a back passivated solar battery. The back polishing process comprises the following steps of generating a silicon nitride mask with a certain thickness and a protective function on the front of a silicon wafer; and performing moderate corrosion on the back of the silicon wafer by using a heated concentrated alkaline solution to achieve a polishing effect. The process is a low-cost chemical polishing method, is economic and applicable, and is suitable for industrial production; a chemical solution is easy to treat, common factory water treatment can completely solve the treatment problem, and the treatment is economic and environment-friendly.

Description

A kind of polished backside technology of making based on back of the body passivation solar cell

Technical field

The invention belongs to the high-efficiency crystal silicon solar cell and make the field, be specifically related to a kind of polished backside technology of carrying on the back in the making of passivation solar cell.

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Background technology

In back of the body passivation solar cell fabrication process, polished backside technology is by chemical means the non-diffusingsurface of crystal silicon chip to be carried out surface treatment, and the microcosmic of namely filling and leading up on the machined surface is uneven, obtains the minute surface of light.

Photovoltaic silicon crystal back of the body passivation solar cell very difficult breakthrough always in the industry at present, key factor just is that the key technology of polished backside technology does not obtain breaking through, at present the glossing in the industry has two kinds of chemical polishing and mechanical polishinges, list mechanical polishing from polishing effect is inferior to chemical polishing anything but, but mechanical polishing device is expensive and production capacity is on the low side, is not suitable for the use of large-scale production.

And chemical polishing appts on the market seldom and technology also immature, key reason has: (1) wants the bonding mirror polish then to need to locate very accurately, present chain equipment is difficult to accomplish absolute single face corrosion; (2) bubble of single-sided polishing technology generation in service is intercepted and can't discharge by silicon chip, sticks to the aeration polishing effect on the silicon chip; (3) acid polishing cost costliness, very big to the pollution of environment, the sewage disposal difficulty increases.

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Summary of the invention

The technical problem to be solved in the present invention is that the defective at prior art exists provides OnePlant economic and practical chemical polishing technology.

The present invention in order to realize the technical scheme that above purpose adopts is, a kind of polished backside technology of making based on back of the body passivation solar cell, it is characterized in that, generate thickness greater than 60 nanometers in the silicon chip front earlier, the silicon nitride mask that shields, the high alkali liquid that re-uses heating carries out the moderate corrosion to the silicon chip back side, reaches polishing effect; The alkali mass concentration of described high alkali liquid is at 20%-40%, and the high alkali liquid temperature is controlled at 40 ℃-60 ℃; The time of described corrosion is 30 seconds-300 seconds.

Above-mentioned technology also comprises this step: the silicon chip that will finish above-mentioned moderate corrosion takes out and puts into the pure water rinsing.

Above-mentioned technology also comprises the step of removing silicon nitride mask: will finish the silicon chip of above-mentioned moderate corrosion or HF solution that its silicon chip by rinsing in the pure water is put into low concentration and soak, to remove silicon nitride mask.

When the thickness of above-mentioned silicon nitride mask was 60 nanometers-62 nanometer, the mass concentration of above-mentioned HF solution was 4%-6%, and the time of above-mentioned immersion is 580 seconds-620 seconds; If silicon nitride film thickness increases, soak time is corresponding increase also.

In the above-mentioned technology, use tubular type PECVD to generate silicon nitride mask.

Above-mentioned high alkali liquid is KOH or NaOH solution.

Above-mentioned high alkali liquid is to heat in water-bath.Use the water-bath heating to make the alkali liquid temperature in the water bath can access stable control, temperature fluctuation is smaller.

The present invention not only can reach the needed polishing effect of industry, and economic and practical, is fit to big production and uses.Because the chemicals that use cost is lower is realized good polishing effect, the processing of chemical liquids is also very simple, and general plant water is handled and can be solved fully.

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Description of drawings

Fig. 1 is the polishing fluid water-bath heating work platform schematic diagram in the invention process.

In last figure: 1-alkali lye cell body; 2-alkali lye; The 3-crystal silicon chip; The 4-heater coil; 5-water; 6-water-bath cell body.

Fig. 2 is the back of the body passivation manufacture of solar cells whole process figure example one that has comprised glossing of the present invention.

Fig. 3 is the back of the body passivation manufacture of solar cells whole process figure example two that has comprised glossing of the present invention.

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Embodiment

The polishing fluid that the present invention uses is alkaline solution, therefore when making the polishing mask, selected alkali resistance mask silicon nitride film, in crystal silicon solar energy battery is produced, therefore the grown silicon nitride film operation that is absolutely necessary realizes that at the crystal silicon solar energy battery production line growth fraction of silicon nitride film is easier to.

The quality of mask has determined in the protection process degree of protection to non-burnishing surface; fine and close silicon nitride film can be protected well and silica-basedly do not corroded; therefore tubular type PECVD(Plasma Enhanced Chemical Vapor Deposition plasma enhanced chemical vapor deposition method is used in suggestion) come growing film to realize better protection, the above thickness of 60 nanometers can reach the effect of protection generally speaking.

The alkali lye of high concentration is fine to the corrosive effect of silicon, reach extraordinary polishing effect and just need heavier corrosion, but consider the silicon chip breakage in the subsequent production technology, industrial needs find a balance point, not only guarantee polishing effect but also can not corrode too many, therefore strict control alkali liquid temperature, concentration and etching time are key points of the present invention, seek a good technological balance and will make the coupling of whole technology reach an extraordinary effect.

As shown in Figure 1; a kind of polished backside technology of making based on back of the body passivation solar cell; its step comprises: generate thickness greater than 60 nanometers in the silicon chip front earlier; the silicon nitride mask that shields; re-use that (temperature is 40 ℃-60 ℃ through the KOH of water-bath heating or NaOH solution; mass concentration is 20%-40%) moderate corrosion 30 seconds-300 seconds is carried out at the silicon chip back side, reach polishing effect, take out silicon chip at last and put into the pure water rinsing.

Then need in the HF of low concentration solution, soak if need to remove silicon nitride film, the HF solution of 4%-6% mass concentration need for 580 seconds-620 seconds time could be very clean the silicon nitride film of removal 60 nanometers-62 nanometer, silicon nitride film thickness increases, and soak time also needs to increase could be removed totally.

Key point of the present invention is and must carries out mask protection to the one side of silicon chip earlier, could polish the surface of another side then.Consider the complexity of solar cell making process and the flexibility of process sequence, go for the kinds of processes circuit, as shown in Figures 2 and 3.

The above only is preferred implementation of the present invention, and protection scope of the present invention also not only is confined to above-described embodiment, and all technical schemes that belongs under the thinking of the present invention all belong to protection scope of the present invention.Should be pointed out that for those skilled in the art in the some improvements and modifications that do not break away under the principle of the invention prerequisite, these improvements and modifications also should be considered as protection scope of the present invention.

Claims

1. a polished backside technology of making based on back of the body passivation solar cell is characterized in that, generates thickness greater than 60 nanometers in the silicon chip front earlier, the silicon nitride mask that shields; The high alkali liquid that re-uses heating carries out the moderate corrosion to the silicon chip back side, reaches polishing effect; The alkali mass concentration of described high alkali liquid is at 20%-40%, and the high alkali liquid temperature is controlled at 40 ℃-60 ℃; The time of described corrosion is 30 seconds-300 seconds.

2. according to the described polished backside technology of making based on back of the body passivation solar cell of claim 1, it is characterized in that, the silicon chip of finishing described moderate corrosion is taken out and put into the pure water rinsing.

3. according to claim 1 or 2 described polished backside technologies of making based on back of the body passivation solar cell, it is characterized in that, soak finishing the silicon chip of described moderate corrosion or HF solution that its silicon chip by rinsing in the pure water is put into low concentration, to remove silicon nitride mask.

4. according to the described polished backside technology of making based on back of the body passivation solar cell of claim 3, it is characterized in that, when the thickness of described silicon nitride mask was 60 nanometers-62 nanometer, the mass concentration of described HF solution was 4%-6%, and the time of described immersion is 580 seconds-620 seconds.

5. according to the described polished backside technology of making based on back of the body passivation solar cell of claim 1, it is characterized in that, use tubular type PECVD to generate silicon nitride mask.

6. according to the described polished backside technology of making based on back of the body passivation solar cell of claim 1, it is characterized in that described high alkali liquid is KOH or NaOH solution.

7. according to the described polished backside technology of making based on back of the body passivation solar cell of claim 1, it is characterized in that described high alkali liquid is to heat in water-bath.